Drills for work in rock, reinforced concrete, etc. are disclosed, for example, in U.S. Pat. No. 7,021,872. The helix is primarily meant to remove drill cuttings from the drilled hole. The classic spiral-shaped helices have proven their worth in this respect, not only because of the reliable transport of the drill cuttings but also because of the moderate production effort involved. Especially due to the production methods employed, however, the classic helix entails compromises when it comes to other properties. One aspect is the friction of the helix against the wall of the drilled hole.